Audio CDs have been commercially available since October 1982. They were invented in 1976, and first publicly demonstrated in on March 8, 1979 at a press conference in the Netherlands. But in radioland it was a long slow process to adoption. We were still largely vinyl-based into the late 1980s. Some stations dubbed them onto carts. But, most stations were still using vinyl and CDs side-by-side in the studio into the 1990s. It was only the later step into digital databases that started to really eliminate the turntable from from the studio.But in radio we play singles, so at commercial stations spinning vinyl, this meant a lot of 45s. Not to belabor the point but these images are from two 45 rpm sleeves from the library of 1220 WSCR-AM, Hamden, CT. Back then it was a country music station. You can see from the notations above that these were dubbed onto carts (Fidelipac) to reduce vinyl wear and every 5 to 10 days they re-dubbed it to tape to keep the audio quality high. Tape can wear quickly. With this rotating system of dubs, the tape always has a fresh copy, and the single gets 1 spin a week instead of 1 every few hours.
Today 1220 in Hamden is WQUN-AM owned by Quinnipiac University and runs full service: sports, news and adult standards. I'm curious to know if the turntable is even still hooked up.